In the manufacture of semiconductors and microchips, one method of manufacture is to use a large wafer of semiconductor material such as silicon dioxide and manufacture many microchips out of a single wafer. The wafer is then separated into the individual microchips. Manufacturing by using the single wafer has the advantage of increasing throughput in the semiconductor manufacturing process. Obviously the larger the wafer that can be used the more efficiency is obtained and the higher the throughput will be. However, since microchips contain many circuits of minuscule dimensions, the manufacturing process must be very precise and accurate to ensure that all microchips manufactured out of a single wafer are of the same quality.
One step in assuring quality and uniformity in the semiconductor manufacturing process is to manufacture the semiconductor wafer in a “clean” environment. Semiconductors are typically manufactured in what is known in the industry as a clean room. A clean room is designed to minimize the number of particulates in the air. The cost of manufacturing and maintaining these clean rooms is very expensive, and therefore any progress that can be made towards reducing the size of the semiconductor manufacturing machines will allow for smaller clean rooms.
While minimizing the size of the manufacturing machine is essential in reducing cost of the clean rooms, it is also necessary to maintain the high quality of the manufacturing in the smaller machines. Since, as described earlier, it is advantageous to use larger wafers to increase throughput, any process to which the wafer is exposed must assure that all portions of the wafer are treated equally. Any unevenness in application of material to the wafer will result in semiconductor chips which are not of sufficient quality and must be destroyed.
One of the processes in the manufacture of semiconductor wafers is electroplating a conductive metallic surface onto the wafer. The electroplating process requires the handling of a large volume of liquid which necessarily implies the use of pumps, piping, and other components, all of which take up valuable space in a clean room environment. Additionally, in the electroplating process, it is necessary to apply an electric current to the semiconductor wafer to cause the electrolytic solution to plate out the conductive metal on the surface of the semiconductor wafer. As described earlier, it is desirable to minimize processing time in the manufacture of the wafer. Therefore, it is desirable to find a fast and efficient method for making the electrical contact to the semiconductor wafer.
It is also desirable that the semiconductor wafer be held in a precise position during the electroplating process to assure uniformity of the conductive metal surface plated onto the wafer. It is therefore desirable to have an apparatus that will present the wafer to the process and hold the wafer in the process in an accurate position.
Finally, it is desirable to have an apparatus which will handle the wafers in a fast and efficient method to increase throughput.
It is against this background that the apparatus of the present invention was developed.